Marine propulsor with inlet fluid inducer

ABSTRACT

Presented is a fluid propulsor for propelling a vehicle that incorporates a Coanda Effect Inducer (CEI), more commonly called an inlet fluid inducer in this application, in its inlet to induce fluids passing by the vehicle to turn uniformly toward a powered fluid energizing device such as a rotor of the propulsor. This concept enhances the efficiency of the rotor and the overall efficiency of the propulsor. The rotor is preferably at least primarily enclosed in a housing and the rotor may operate either fully submerged in liquid or in a partially liquid and partially gaseous environment. Fluid flow directing devices may be incorporated to separate liquid from gas flowing to the rotor in some instances. The inlet fluid inducer may take the shape of a cylinder or any other flow directing shape and while more effective when rotating in the direction of fluid flow is also viable when not rotating.

CROSS REFERENCE TO OTHER APPLICATONS

This application is a continuation-in-part to applicant's earlier applications: Ser. No. 11/088,212 filed Mar. 18, 2005 and Ser. No. 11/373,620 filed Mar. 10, 2006.

BACKGROUND OF THE INVENTION

Enclosed rotor propulsion system for marine craft, such as waterjets and Applicant's enclosed ventilated rotor Hydro Air Drive® (HAD) invention, are limited in the overall efficiency they can realize by the efficiency of recovery by their water inlets of the fluid available at their water inlets. As an example, waterjets can have very high efficiency rotors, stator vanes that straighten the discharge flow of the rotors, and discharge nozzles. The overall efficiency of the just mentioned three items are in the 90% or higher area for a well designed high power level waterjet.

However, the overall efficiency of a waterjet is severely limited by its inlet's ability to recovery oncoming fluids efficiently. This is because the oncoming fluid flow is forced to turn into the duct that surrounds the waterjet's rotor. As an example, a waterjet's inlet may see efficiencies of fluid recovery of 92% over its lower half but only 54% or so over its upper half. This is because the fluid flow is separating over the upper part of the inlet duct as it is trying to turn from the inlet toward the rotor. This is so even though the waterjet operates as an enclosed pressurized system and thereby is creating suction at its inlet.

The HAD sees a slightly different situation in that it is not a pressurized system and therefore does not create much of a suction at its inlet. The advantage of the HAD is that it only operates with the lower half of its rotor submerged so its inlet fluid does not have to turn as far as does the waterjet's. However, the lack of inlet suction of the HAD does hamper the ability of its inlet to fully recovery fluid approaching its inlet.

What all of this means is that propulsors, such as waterjet and the HAD, would benefit greatly by having water inducer devices at their inlets. As a side point, it is realized that having a straight-in inlet with the inlet in-line with the rotor with no turns would provide high inlet efficiencies. The obvious problem with this is twofold, to wit: 1) Excessive drag due to high frontal area and 2) Very deep draft. Therefore the approach of an inline inlet is generally impractical.

The Coanda Effect can be used for turning fluids around curved surfaces and has been known for many years. This Coanda Effect can be improved by use of a rotating cylinder or other curvilinear shape placed perpendicular to or at least partially perpendicular to the fluid flow to entice the fluid to turn in the direction of rotation of the rotating surface. The instant invention takes advantage of these known sciences and places a Coanda Effect Inducer (CEI) at or near the entrance of the inlet of the propulsor. The effect of this is to greatly improve the recovery of fluids flowing past the propelled vehicle and of delivering such fluids to a fluid energizing device, such as a rotor, of the propulsor. This greatly improves the overall efficiency of the propulsor and hence the performance of the vehicle. The CEI is commonly called an inlet fluid inducer herein.

A discussion of the instant invention and the advantages it offers is presented in detail in the following sections.

OBJECTS OF THE INVENTON

A primary object of the invention is provide an improved propulsor for propelling a vehicle where said propulsor accelerates fluid to produce thrust and where said fluid is obtained through an inlet that intakes fluid from external to the vehicle and directs said fluid toward a fluid energizing device wherein said inlet includes an inlet fluid inducer and wherein said inlet fluid inducer directs said fluid toward a fluid energizing device such as a powered rotor.

A related object of the invention is that the inlet fluid inducer may rotate.

A directly related object of the invention is that the inlet fluid inducer provide a uniformity to the energy in the fluid supplied to the fluid energizing device.

A related object of the invention is that said inlet fluid inducer be oriented more perpendicular to than parallel to a plane that includes a rotational axis of the fluid energizing device.

A further object of the invention is that the inlet fluid inducer be capable of rotation in the direction of fluid flow.

Yet another object of the invention is that the inlet fluid inducer extend less than 60 percent of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.

A directly related refining object of the invention is that said inlet fluid inducer extend less than 40 percent of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.

A further directly related refining object of the invention is that said inlet fluid inducer extend less than 20 percent of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.

Yet another object of the invention is that the inlet fluid inducer may rotate freely in the direction of fluid flow through 360 degrees of rotation with no powering means.

Another object of the invention is that the inlet fluid inducer may be driven by a power source that also drives the fluid energizing device through 360 degrees of rotation.

A directly related object of the invention is that a drive shaft of a fluid energizing device may also drive the inlet fluid inducer.

Still another object of the invention is that the fluid energizing device may receive primarily liquid over one portion of its rotation and primarily gas over another portion of its rotation.

A related object of the invention is that a fluid directing device may be disposed at least in its majority downstream of the inlet fluid inducer.

A directly related object of the invention is that the fluid directing device has the ability to, in at least one mode of its operation, restrict gas from passing to the fluid energizing device.

Another object of the invention is that the fluid directing device be powered by an actuator.

Yet another object of the invention is that the inlet fluid inducer may include recesses in its periphery that are capable of energizing fluids when the inlet fluid inducer is rotating.

A further object of the invention is that the inlet fluid inducer may be driven with gears.

Still another object of the invention is that the fluid energizing device be a rotor.

An optional object of the invention is that the fluid discharge from the fluid energizing device may be given direction by a rudder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a centerline cross-sectional profile view of a prior art waterjet propulsor.

FIG. 2 presents a cross-section, as taken through plane 2-2 of FIG. 1, that shows the general values of recovery of fluids by the inlet as seen at a plane just forward of the fluid energizing rotor that can be expected in a commercial waterjet based on present day designs. Note that the overall inlet efficiency, based on 92% in the lower half and 54% in the upper half, comes to only about 73%.

FIG. 3 is the same centerline cross-sectional profile view as given in FIG. 1 but in this case a Coanda Effect Inducer (CEI), also called as an inlet fluid inducer herein, has been added as is a preferred embodiment of the instant invention. The direction of rotation of this inlet fluid inducer here aids in directing the inlet water in a uniform manner to the fluid energizing rotor. Note that the fluid inlet inducer is shown as being able to rotate through a full 360 degrees of rotation here which is the preferred method of operation. However, it may also be fixed in position where, while not as efficient in so doing, it will also provide the Coanda effect of turning the inlet fluid upward toward the rotor. The fluid inlet inducer may have its rotation powered or non-powered where in the latter case it is free-wheeling.

FIG. 4 gives a cross-section, as taken through line 4-4 of FIG. 3, that gives the predicted values for the recovery of fluids by the inlet with the inlet fluid inducer rotating. Note that the recovery value over fluids entering the lower portion of the fluid energizing device is 96% and over the upper portion 90%. This results in an overall inlet efficiency of 93%. The very important result is that there is about a twenty-five percent improvement in overall efficiency for a waterjet with the inlet fluid inducer compared to one without an inlet fluid inducer.

FIG. 5 illustrates a proposed version of a inlet fluid inducer, as taken through plane 5-5 of FIG. 3, that shows one possible means of driving this cylindrical shaped inlet fluid inducer. In this particular case the drive means consists of a drive motor with power transmitted through a set of right angle gears.

FIG. 6 presents a cross-section, as taken through line 6-6 of FIG. 3, that shows a preferred flat surface forward to the inlet fluid inducer. Note that the lower surface of the inlet fluid inducer is disposed more into the oncoming fluid than surfaces of the hull forward of the inlet fluid inducer in this example. This preferred approach insures optimum performance of the inlet fluid inducer while adding very little additional drag.

FIG. 7 presents a partial profile centerline cross-section of a HAD with an instant invention inlet fluid inducer applied. There are, ideally, fluid directing means—flaps in this illustration—applied to either side of the shaft here. In this instance, the fluid directing means are retracted to their most upward positions which allows water to flow to the entire HAD fluid energizing rotor from top to bottom. This is the preferred position of the fluid directing means for low vehicle speed operation when maximum low speed thrust is desired.

FIG. 8 is the same partial profile centerline cross-section of a HAD as presented in FIG. 7 but in this case the fluid directing means are extended downward to aid in directing fluids to only a portion of the fluid energing rotor. It is important to note also that a lowered position of the fluid directing means allows gas to pass to the upper portion of the fluid energizing rotor. As such, the rotor is operating only partially submerged which has advantages compared to standard pressurized system waterjets. These advantages are discussed later in this application.

FIG. 9 is a cross-sectional plane, as taken through 9-9 of FIG. 7, that shows the fluid directing means in their retracted position. Note that in this position the fluid directing means restrict the flow of gases to the fluid energizing device which is normally a rotor with blades.

FIG. 10 is a cross-sectional plane, as taken through 10-10 of FIG. 8, that illustrates how the fluid directing means are positioned during high speed vehicle operation where the fluid energizing device such as a rotor is only partially submerged.

FIG. 11 presents a cross-sectional plane, as taken through line 11-11 of FIG. 7, that shows the fluid flow distributions just forward of the fluid energizing rotor when the fluid directing means are in their retracted position.

FIG. 12 is a cross-sectional plane, as taken through line 12-12 of FIG. 8, that illustrates fluid flow distributions just forward of the fluid energizing rotor when the fluid directing means are in an extended high vehicle speed position. Note that there is gas above the fluid directing means and water below it in this instance. Inlet recovery efficiencies should be in the 98% area over the lower half of the fluid energizing rotor in this instance.

FIG. 13 illustrates fluid flow inlet characteristics when the inlet fluid inducer is not rotating. While this is very workable and considered part of the instant invention, performance is substantially better when the inlet fluid inducer is rotating in the direction of the water flow.

FIG. 14 shows a cross-sectional plane, as taken through line 14-14 of FIG. 13, that illustrates water flow characteristics with the inlet fluid inducer not rotating. Comparing this FIG. 13 to FIG. 12 gives some idea of the expected performance improvements to having the inlet fluid inducer rotating.

FIG. 15 illustrates flow characteristics around a non-rotating cylinder disposed perpendicular to fluid flow. Note that the flow separates around the aft side of the cylinder.

FIG. 16 shows the same cylinder as that presented in FIG. 15 but with the cylinder rotating. It is apparent that the fluid does not detach as is the case of the non-rotating cylinder of FIG. 15. This rotating cylinder makes for a much more efficient and low drag situation than the non-rotating cylinder of FIG. 15. Both FIGS. 15 and 16 actually show characteristics of the Coanda Effect since the fluid is at least partially attached to the curvilinear surfaces and turn inward in both instances.

FIG. 17 shows the same HAD unit as shown previously; however, in this case the inlet fluid inducer is cylindrical and rotating in an opposite direction to travel and freestream fluid flow. This has merit in a case where a HAD or waterjet is not operating but the vehicle is still moving forward as would be the case of operating with their drive engine out but with other propulsors still operating. The reason this is so is that the forward direction of rotation of the inlet fluid inducer directs oncoming fluids away form the HAD's inlet thereby reducing drag forces that would occur with fluid entering a non-operating unit.

FIG. 18 presents a centerline profile cross-section plane that shows an alternate method of driving an inlet fluid inducer. In this case the inlet fluid inducer is directly driven by a main drive shaft of a propulsor. Also, this figure shows how an inlet fluid inducer could work when operating in reverse as is the inlet fluid inducer here. Running the inlet fluid inducer in reverse, either powered or non-powered, along with reverse operation of the rotor results in enhanced reverse thrust.

FIG. 19 presents a cross-section plane, as taken through 19-19 of FIG. 18.

FIG. 20 is a cross-section plane, as taken through 20-20 of FIG. 18. The inlet fluid inducer illustrated here is in the form of truncated cones either side of a gear drive track. Realize that the inlet fluid inducer can take many shapes to accommodate different hull shapes, inlet designs, and the like.

FIG. 21 is another cross-section plane, as taken through 21-21 of FIG. 18, that shows an optional elliptical, as seen in this cross-section, shaped inlet fluid inducer.

FIG. 22 shows yet another version of an inlet fluid inducer that in this case is made up of two separate parts.

FIG. 23 is a partial centerline cross-section plane with a variation of an inlet fluid inducer that incorporates pumping recesses to enhance pumping or fluid accelerating abilities of the inlet fluid inducer.

FIG. 24 is a cross-section plane, as taken through 24-24 of FIG. 23, that shows the preferred shape and workings of the inlet fluid inducer variation of FIG. 23.

DETAILED DESCRIPTION

FIG. 1 shows a centerline cross-sectional profile view of a prior art waterjet propulsor 53 as it is propelling a vehicle 39 forward at high speed. Note that high speed is defined herein as being forward speeds of 15 knots or more and low speeds as speeds of less than 15 knots. Shown also are the shaft 31, fluid energizing device which in this case is a rotor 42, stator including flow straightening stator vanes 40, and discharge nozzle 41. Other items of interest include inlet housing 34, vehicle hull 39, waterline 45, waterflow arrows 37, turbulent water flow arrows 50, and thrust arrow 51. The power source is not shown to simplify the drawings. Note that the turbulent water flow arrows 37 indicate that the water flow is separating over the upper surface of the inlet housing 34.

FIG. 2 presents a cross-section, as taken through plane 2-2 of FIG. 1, that shows the general values of recovery of energy available at the inlet 55 in a plane just forward of the rotor 35 as can be expected in a large commercial waterjet 53 to today's technology. The overall inlet efficiency can be approximately determined from the inlet pressure islands 47. Note that the approximate overall inlet efficiency, based on 92% in the lower half and 54% in the upper half, comes to only 73%.

FIG. 3 is the same centerline cross-sectional profile view as given in FIG. 1 but in this case a Coanda Effect Inducer (CEI), more commonly called an inlet fluid inducer 30 herein, has been added as is a preferred embodiment of the instant invention. The direction of rotation, as shown by rotation arrow 49, of this inlet fluid inducer 30 aids in directing and adding energy to the recovered incoming fluid as it is directed to the fluid energizing device such as rotor 42. Note that the fluid inlet inducer 30 is shown as being able to rotate through a full 360 degrees of rotation here which is the preferred method of operation. However, it may also be fixed in position where, while not as efficient in so doing, it will also provide the Coanda effect of turning the inlet fluid upward toward the rotor. The fluid inlet inducer 30 may have its rotation powered, the most efficient means for turning the inlet fluid upward toward the rotor 42, or non-powered where in the latter case it is free-wheeling.

The dimension A given in FIG. 3 shows that the inlet fluid inducer 30 can extend below the average depth of the hull portion 39 forward of the inlet fluid inducer 30. Having the inlet fluid inducer 30 on average lower than the hull portion 39 forward of it allows the inlet fluid inducer 30 to operate more efficiently and in cleaner water. This is done with very little addition to the drag of the inlet as will be discussed later in the descriptions of FIGS. 15 and 16.

In FIG. 3 and subsequent figures in this application, dimension A is best defined as a percentage of the diameter of the inlet fluid inducer 30 and may extend to as much as 60 percent or more of the diameter of the inlet fluid inducer 30 and offer advantage in efficiency of recovery of fluids external to the inlet and still add little drag to the vehicle. For purposes of this application, the amount that the inlet fluid inducer 30 can extend beyond the average height of a hull portion 39 forward of the inlet fluid inducer 30 is either not specified or defmed as less than 60% of inlet fluid inducer 30 diameter, less than 40% of inlet fluid inducer 30 diameter, or less than 20% of inlet fluid inducer 30 diameter. It is to be noted that the term diameter used here can actually be the maximum dimension of the inlet fluid inducer 30 that is perpendicular to fluid flow as could be the case for shapes other than cylindrical.

Each of these extensions, relative to the hull portions, have advantages and disadvantages. For example, in the case of a Surface Effect Ship (SES) such as applicant's SeaCoaster® that is supported by pressurized gas cushions with the propulsor inlets disposed at least primarily aft of the gas cushions it is best to have the inlet fluid inducer 30 extend beyond the hull portion in front of it as far as possible. This is because the gas cushions aerate the water and there may also be a layer of gas between the hull 39 and the water surface when it reaches the propulsor's water inlet. Having the inlet fluid inducer 30 extend outward beyond the hull means that its outward portions can work in relatively clean gas free liquid. Contrarily, it is desirable to have the inlet fluid inducer 30 not so far extended for a very high speed craft.

Large displacement hulls may find extension of the inlet fluid inducer 30 to work best when at low values also. This is because of the boundary layer associated with large displacement hulls and the desire to take in water to the propulsor from close to the hull where it has already been brought up to near ship speed. The advantage of the instant invention in such a displacement hull application is that the propulsor gets an added thrust advantage from taking in the ship's accelerated boundary layer rather than quiescent water in outer reaches of the boundary layer. It is further to be noted that the instant invention may be disposed so that it is actually has all or part of its inlet higher than its fluid energizing rotor as would be the case when operating on the upper or side surfaces of hydrofoil, submarine, or other submerged or partially submerged vehicle.

Burg, U.S. Pat. No. 6,827,616 shows a flap-like inlet fluid inducer 46 capable of rotation by power actuator 47 to direct fluids toward his fluid energizing device 41. Burg's flap-like fluid inducer 46 is incapable of rotation through 360 degrees nor does his flap-like device 46 extend below the outlines of his hull which is the preferred embodiment of the instant invention especially when the instant invention's fluid inlet inducer 30 is fixed and not rotating. Willyard, U.S. Pat. No. 4,070,046, shows a rotational device 16 that is capable of 360 degrees of rotation; however, his rotational device 16 does not supply fluids to a powered fluid energizing device as does the instant invention. Rather, Willyard's rotational device 16 is at the bow of his vessel and actually is the only source supplying energy for propelling his vessel since it accelerates fluids rearward and out a duct in the bottom of his vessel. Willyard also shows a variation, in his FIGS. 11-13, where he has a propeller like device 32, also at the bow of his vessel, that accelerates fluids rearward to provide forward thrust. Neither of Willyard's variations has application to the instant invention since he has no powered fluid energizing device and his rotational device 16 is actually his powered fluid energizing device.

FIG. 4 presents a cross-section, as taken through line 4-4 of FIG. 3, that gives the predicted values for the recovery of the inlet fluid with the inlet fluid inducer 30 rotating as shown. Note that the expected recovery over the lower portion of the fluid energizing rotor is 96% and over the upper portion 90%. This results in an overall inlet efficiency of 93%. The net result is about a twenty-seven percent improvement in overall waterjet efficiency for a waterjet with the inlet fluid inducer compared to one without.

FIG. 5 illustrates a proposed version of an inlet fluid inducer 30, as taken through plane 5-5 of FIG. 3, that shows one possible means of driving this cylindrical shaped inlet fluid inducer 30. In this case the drive means consists of a drive motor 43 with power transmitted through a set of right angle gears 44. The drive motor 43 may be driven electrically, hydraulically, or by other means.

FIG. 6 presents a cross-section, as taken through line 6-6 of FIG. 3, that shows a preferred flat hull 39 surface forward to the inlet fluid inducer 30. Note that the lower surface of the inlet fluid inducer 30 is disposed more into the freestream than surfaces forward of the inlet fluid inducer 30 as shown here. This preferred approach shown here insures optimum performance of the inlet fluid inducer 30 while adding very little additional drag. However, it is to be realized that, while the arrangement shown is preferred, that the instant invention's inlet fluid inducer 30 can actually be flush with the hull 30 surfaces or even recessed from them and such arrangements are considered within the spirit and scope of the instant invention.

FIG. 7 presents a partial profile centerline cross-section of a Hydro Air Drive (HAD) 54 with an instant invention inlet fluid inducer 30 applied. There are, ideally, fluid directing means 33—flaps in this illustration—applied. These flaps 33 are to either side of the shaft 31 in this preferred arrangement of the instant invention. In this FIG. 7, the fluid directing means 33 are retracted to their most upward positions with power supplied by actuators 32 which allows water to flow to the entire HAD fluid energizing rotor 35 from top to bottom. This is the preferred position of the fluid directing means 33 for low vehicle speed operation to provide maximum low speed thrust.

Another item of note in FIG. 7 is the optional use of low cost and low maintenance labyrinth seals 52 to restrict water from flowing freely around the inlet fluid inducer 30. While the fluid inlet 55 is shown below the fluid energizing rotor 35 here it is to be realized that it can be fully or partially to the side of or even above the fluid energing rotor 35 as a particular installation may dictate. An optional rudder 36 that provides steering in forward and in reverse is also shown.

FIG. 8 is the same partial profile centerline cross-section of a HAD 54 as presented in FIG. 7 but in this case the fluid directing means 33 are extended downward to aid in directing liquid flow to only a portion of the fluid energizing rotor 35. It is important to note also that a lowered position of the fluid directing means 33 allows gas to pass to the upper portion of the rotor 42 through gas passageways 57 as is indicated by gas flow arrows 38. As such, the fluid energizing rotor 35 is operating only partially submerged which has advantages compared to standard pressurized system waterjets. Two of these advantages are: 1) The HAD rotor is not subject to cavitation damage since it is aerated and 2) Ingestion of aerated water by the HAD does not result in a severe performance decay it does in the case of a standard pressurized system waterjet.

FIG. 9 is a cross-sectional plane, as taken through 9-9 of FIG. 7, that shows the fluid directing means 33 in their retracted position. Note that gas flow is restriced from entering the duct and from reaching the fluid energizing rotor 35 since it is blocked from doing so by the fluid directing means 33.

FIG. 10 is a cross-sectional plane, as taken through 10-10 of FIG. 8, that illustrates how the fluid directing means 33 are positioned during high speed vehicle operation where the fluid energizing rotor 35 is only partially submerged. Note the gas flow arrows 38 that show that gas is passing through in this arrangement. Waterlines 45 either side of the instant invention propulsor 54 are also shown.

FIG. 11 presents a cross-sectional plane, as taken through line 11-11 of FIG. 7, that shows the fluid flow distributions, as indicated by fluid energy islands 47, just forward of the fluid energizing rotor when the fluid directing means are in their retracted position.

FIG. 12 is a cross-sectional plane, as taken through line 12-12 of FIG. 8, that illustrates fluid flow distributions, as indicated by fluid energy islands 47, just forward of the fluid energizing rotor when the fluid directing means are in an extended high vehicle speed position. Note that there is gas above the fluid directing means and liquid below it in this instance. Inlet recovery efficiencies should be in the 98% area over the lower half of the fluid energizing rotor in this instance where the inlet fluid inducer is rotating and adding energy and direction to the incoming fluids.

FIG. 13 illustrates fluid flow inlet characteristics when the inlet fluid inducer is not rotating. While this is very workable and considered part of the instant invention, performance is substantially better when the inlet fluid inducer is rotating in the direction of the water flow. Expected inlet recoveries should be in about the 80% area in this case with the inlet fluid inducer not rotating. Note also that the waterline 45 is lower than in the case where the inlet fluid inducer is rotating as seen in FIG. 12 so the fluid energizing rotor would most likely not be receiving as much liquid as the fluid energizing rotor of FIG. 12.

FIG. 14 shows a cross-sectional plane, as taken through line 14-14 of FIG. 13, that illustrates liquid flow characteristics with the inlet fluid inducer not rotating. Note the lower waterline 45 here than in FIG. 12. Also, the expected recovery is 80% while it is 98% in FIG. 12 where the inlet fluid inducer is rotating in the direction of fluid flow.

FIG. 15 illustrates flow characteristics around a non-rotating cylinder 48 disposed perpendicular to ideal fluid flow. Note that the flow, indicated by turbulent flow lines 50, separates around the aft side of the cylinder 48.

FIG. 16 shows the same cylinder 48 as that presented in FIG. 15 but with the cylinder 48 rotating in the direction of flow as is indicated by rotation arrow 49. It is apparent that the fluid does not detach as is the case of the cylinder 48 that is not rotating of FIG. 15. This rotating cylinder 48 makes for a much more efficient and low drag situation than the cylinder 48 that is not rotating of FIG. 15. Both FIGS. 15 and 16 actually show characteristics of the Coanda Effect since the fluid is at least partially attached to the curvilinear surfaces on the aft side of the cylinder 48 and turn inward.

FIG. 17 shows the same HAD 54 as shown previously; however, in this case the inlet fluid inducer 30 is rotating in an opposite direction to travel and external fluid flow. This has merit in a case where a HAD or waterjet is not operating but the vehicle is still moving forward since this forward direction of rotation of the inlet fluid inducer 30 prevents water from entering the HAD's inlet 55 thereby reducing drag.

FIG. 18 presents a centerline profile cross-section plane that shows an alternate method of driving an inlet fluid inducer 30. In this case the inlet fluid inducer 30 is directly driven by a main drive shaft 31 of the propulsor. Also, this figure shows how an inlet fluid inducer 30 could work when operating in reverse as is the inlet fluid inducer 30 here. Running the inlet fluid inducer 30 in reverse along with reverse operation of the fluid energizing rotor results 35 in enhanced reverse thrust.

FIG. 19 presents a cross-section plane, as taken through 19-19 of FIG. 18. Note that the fluid flow directing means 33 are retracted here.

FIG. 20 is a cross-section plane, as taken through 20-20 of FIG. 18. The inlet fluid inducer 30 illustrated here is in the form of truncated cones either side of a gear track 46. Realize that the inlet fluid inducer 30 can take many shapes to accommodate different hull shapes, inlet designs, and the like.

FIG. 21 is another cross-section plane, as taken through 21-21 of FIG. 18, that shows an optional elliptical shaped inlet fluid inducer 30.

FIG. 22 shows yet another version of an inlet fluid inducer 30 that in this case is made up of two parts.

FIG. 23 is a partial centerline cross-section plane with a variation of an inlet fluid inducer that incorporates pumping recesses 56 to enhance pumping or fluid accelerating abilities of the inlet fluid inducer 30. Note that other manners of shape and of possible recesses in the inlet fluid inducer 30 are considered within the spirit and scope of the instant invention.

FIG. 24 is a cross-section plane, as taken through 24-24 of FIG. 23, that shows a preferred shape and workings of the inlet fluid inducer 30 variation of FIG. 23.

While the invention has been described in connection with a preferred and several alternative embodiments, it will be understood that there is no intention to thereby limit the invention. On the contrary, there is intended to be covered all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims, which are the sole definition of the invention. 

1. In an improved propulsor for propelling a vehicle wherein said propulsor accelerates fluid to produce thrust and wherein said fluid is obtained through an inlet that intakes fluid from external to the vehicle and directs said fluid toward a powered fluid energizing device, the improvement comprising: an inlet fluid inducer wherein said inlet fluid inducer is capable of three hundred sixty degrees of rotation to direct said fluid toward the powered fluid energizing device and thereby provide a uniformity to the fluid supplied to the powered fluid energizing device and wherein said inlet fluid inducer is oriented more perpendicular than parallel to a plane that includes a rotational axis of the powered fluid energizing device.
 2. The improved propulsor of claim 1 wherein the inlet fluid inducer rotates in the direction of fluid flow.
 3. The improved propulsor of claim 1 wherein said inlet fluid inducer extends less than 60 percent of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.
 4. The improved propulsor of claim 1 wherein said inlet fluid inducer extends less than 40 percent of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.
 5. The improved propulsor of claim 1 wherein said inlet fluid inducer is driven by a power source that also drives the powered fluid energizing device.
 6. The improved propulsor of claim 1 wherein said powered fluid energizing device receives primarily liquid over one portion of its rotation and primarily gas over another portion of its rotation.
 7. The improved propulsor of claim 6 wherein a fluid directing device is disposed at least in its majority downstream of the inlet fluid inducer.
 8. The improved propulsor of claim 7 wherein said fluid directing device has ability to, in at least one mode of its operation, restrict gas from passing to the powered fluid energizing device.
 9. The improved propulsor of claim 1 wherein said inlet fluid inducer includes recesses in its periphery that are capable of energizing fluids when the inlet fluid inducer is rotating.
 10. The improved propulsor of claim 1 wherein the powered fluid energizing device is a rotor.
 11. The improved propulsor of claim 1 wherein the fluid inlet inducer, as seen in a plane perpendicular to a longitudinal axis of the fluid inlet inducer, is, on average, circular in cross section.
 12. The improved propulsor of claim 1 wherein the inlet fluid inlet inducer, when said vehicle is moving forward, is capable of free wheeling rotation in a direction of fluid flow when said inlet fluid inducer is not powered.
 13. In an improved propulsor for propelling a vehicle wherein said propulsor accelerates fluid to produce thrust and wherein said fluid is obtained through an inlet that intakes the fluid from external to the vehicle and directs said fluid toward a powered fluid energizing device, the improvement comprising: an inlet fluid inducer wherein said inlet fluid inducer is capable of three hundred degrees of rotation to direct said fluid toward the powered fluid energizing device to thereby provide direction to the fluid supplied to the powered fluid energizing device and wherein the inlet fluid inducer rotates in the direction of fluid flow.
 14. The improved propulsor of claim 13 wherein said inlet fluid inducer is oriented more perpendicular than parallel to a plane that includes a rotational axis of the powered fluid energizing device.
 15. The improved propulsor of claim 13 wherein said inlet fluid inducer extends less than 60 percent of its of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.
 16. The improved propulsor of claim 13 wherein said inlet fluid inducer extends less than 40 percent of its of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.
 17. The improved propulsor of claim 13 wherein said inlet fluid inducer is driven by a power source that also drives the powered fluid energizing device.
 18. The improved propulsor of claim 13 wherein said powered fluid energizing device receives primarily liquid over one portion of its rotation and primarily gas over another portion of its rotation.
 19. The improved propulsor of claim 13 wherein a fluid directing device is disposed at least in its majority downstream of the inlet fluid inducer.
 20. The improved propulsor of claim 19 wherein said fluid directing device has ability to, in at least one mode of its operation, restrict gas from passing to the powered fluid energizing device.
 21. The improved propulsor of claim 13 wherein said inlet fluid inducer includes recesses in its periphery that are capable of energizing fluids when the inlet fluid inducer is rotating.
 22. The improved propulsor of claim 13 wherein the fluid inlet inducer, as seen in a plane perpendicular to a longitudinal axis of the fluid inlet inducer, is, on average, circular in cross section.
 23. The improved propulsor of claim 13 wherein the inlet fluid inlet inducer, when said vehicle is moving forward, is capable of free wheeling rotation in a direction of fluid flow when said inlet fluid inducer is not powered.
 24. In an improved propulsor for propelling a vehicle wherein said propulsor accelerates fluid to produce thrust and wherein said fluid is obtained through an inlet that intakes the fluid from external to the vehicle and directs said fluid toward a powered fluid energizing device, the improvement comprising: an inlet fluid inducer wherein said inlet fluid inducer is capable of three hundred sixty degrees of rotation to direct said fluid toward the powered fluid energizing device and thereby provide uniformity to the fluid supplied to the powered fluid energizing device and wherein said inlet fluid inducer extends less than 60 percent of its maximum dimension perpendicular to fluid flow beyond an average height of a vehicle hull portion when said vehicle hull portion is viewed proximal to, forward of, and in line with the inlet fluid inducer.
 25. The improved propulsor of claim 24 wherein said inlet fluid inducer is oriented more perpendicular than parallel to a plane that includes a rotational axis of the powered fluid energizing device.
 26. The improved propulsor of claim 24 wherein said inlet fluid inducer is driven by a power source that also drives the powered fluid energizing device.
 27. The improved propulsor of claim 24 wherein said fluid energizing device receives primarily liquid over one portion of its rotation and primarily gas over another portion of its rotation.
 28. The improved propulsor of claim 24 wherein a fluid directing device is disposed at least in its majority downstream of the inlet fluid inducer.
 29. The improved propulsor of claim 28 wherein said fluid directing device has ability to, in at least one mode of its operation, restrict gas from passing to the powered fluid energizing device.
 30. The improved propulsor of claim 24 wherein the fluid inlet inducer, as seen in a plane perpendicular to a longitudinal axis of the fluid inlet inducer, is, on average, circular in cross section.
 31. The improved propulsor of claim 24 wherein the inlet fluid inlet inducer, when said vehicle is moving forward, is capable of free wheeling rotation in a direction of fluid flow when said inlet fluid inducer is not powered. 